Cut-off value of walking ability for determining early gait independence in patients after total knee arthroplasty:

A study evaluating the two-step test

Abstract

Objectives: To investigate the reliability and validity of the two-step test as an assessment of walking ability in the early postoperative period after knee arthroplasty and to determine a “cut-off” value to discriminate gait independence.

Methods: A total of 106 patients who underwent primary unilateral knee arthroplasty were included. The degree of walking independence and physical function (pain and range of motion of the knee joint) were assessed one week after surgery. In addition, walking ability (walking speed, etc.) assessments including the two-step test were performed. Reliability was assessed by obtaining the intraclass correlation coefficient from the two-step test scores on the operative side and the nonoperative sides and by examining the systematic error using Bland-Altman plots. The validity of the results was examined based on the correlation between the two-step test scores, walking ability, and physical function. The cut-off value of the two-step test score to discriminate gait independence was determined from the ROC curve.

Results: Reliability was good, and no systematic error was observed. The Two-step test scores were more strongly correlated with walking ability than with physical function, and a cut-off value for gait independence was determined.

Conclusions: The two-step test is a reliable and valid assessment method for evaluating gait ability that has a “cut-off” value for determining gait independence even in early postoperative patients after knee replacement surgery.